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About Michael J. Miller

Miller, who was editor-in-chief of PC Magazine from 1991 to 2005, authors this blog for PC Magazine to share his thoughts on PC-related products. No investment advice is offered in this blog. All duties are disclaimed. Miller works separately for a private investment firm which may at any time invest in companies whose products are discussed in this blog, and no disclosure of securities transactions will be made.

Before the conference even officially started, AMD, Qualcomm, and the other members of the Heterogeneous Systems Alliance (HSA) were pushing the upcoming HSA specifications designed to make an SoC (system-on-chip) with different kinds of processors work better together, with a more unified memory model. Initially, this is aimed at making the CPU and on-die graphics units (GPUs) work in a more unified way, though support for other types of on-die accelerators will come later.

Note this is somewhat different than other approaches such as the Kronos Group's Open CL or Nvidia's CUDA, which both are designed to help manage GPU compute, but are most often used with discrete graphics.

Still, the concept is very similar and indeed many of the tools and libraries that support things like Open CL can be adapted to HSA. The idea is to make it easier to do parallel programming, both for the CPU and the GPU, using standard programming languages. Having processors with all these components sharing high-bandwidth memory is a good start, but they become much more useful as developers can really take advantage of them.

AMD has been talking about the HSA concept for years, and at Hot Chips, the company spent some time talking about the chips it released earlier this year, known as Kabini and Richland.

Kabini, which is marketed as the E-series and the lower end of the A-series, uses quad-core "Jaguar" x86 cores, plus the Radeon HD 8000 Graphics Core Next (GCN) architecture. The company said this "sets us up for heterogeneous computing." AMD said this gives them more than twice the performance per watt of the previous generation (known as Ontario). Kabini uses 914 million transistors and measures 105mm2 on a 28nm process.

Richland, which makes up the higher-end parts of the A-series, is a reworked version of the Trinity chip, still manufactured on a 32nm process. This chip has two modules with Piledriver CPU cores (each module has two integer cores and shares floating-point and other features), each with 2MB of shared L2 cache and a Radeon HD 8000 series DX11-capable GPU with six compute units. But the focus of the talk was how AMD was able to improve power management.

Richland adds on-die sensors to measure the temperature, an additional boost state, Configurable TDP for OEMs, and "Intelligent Boost," which detects whether the workload running on CPU is sensitive to frequency. If not, Intelligent Boost can throttle the CPU and deliver more power to the GPU for better overall system performance. Overall, AMD said Richland delivers up to 29 percent better CPU performance and 41 percent better GPU performance than Trinity, and was up to 51 percent more efficient than Trinity in HD video playback. In my own tests, I've found it's still much slower at pure CPU tasks than competing Intel chips but I haven't really focused on battery life. Richland doesn't support HSA—the spec isn't really complete—but the company said it was "probably 60 percent compliant." This will be replaced early next year, with a chip known as Kaveri, which should support more HSA features.

As for Intel, it gave more details on the 4th generation Core processor line, known as Haswell, which began shipping a couple of months ago. It's a family of dual- and quad-core processors, with a variety of different graphics options, now including a version with embedded DRAM for the highest-end graphics variants.

Like the recent generations, Haswell combines the CPU cores and GPU on a single chip with a shared last-level cache and supports standard programming APIs such as OpenCL. But some versions of the 4th generation Core with Iris Pro graphics also include an additional 128MB of eDRAM in the same package, albeit on a separate die.

The larger cache allows the system to speed up existing tasks. For example, the GPU can now save and reuse data from frame to frame to improve 3D gaming performance. While the CPU cores and GPU use the same physical pools of memory, they still use separate pointers, or virtual memory addresses, distinguishing it from the HSA Foundation's more ambitious approach. But it seems fair to say that Intel is headed in the same general direction of using the GPU for more computing workloads and making it easier to program with support for the latest DirectX 11 and OpenCL standards.

Much of the talk dealt with how Haswell better deals with power management. It has a new extremely low-power active state (called S0ix), designed to let the system gather information while using very little power. And Haswell integrates a large number of separate voltage regulators that were separate components in the Ivy Bridge and previous generations.

Other changes include improvements to graphics and media processing, including 4K video playback, and QuickSync video at four to 12 times real-times speed. The core itself has new branch prediction and other features and new compute instructions include AVX2 while the chip adds support for transactional memory for databases and high-performance computing and better virtualization support. My initial tests on Haswell systems showed some performance improvements on real-world benchmarks, but the big news here seems to be battery life, with some systems like the MacBook Air showing significant improvements.

Intel didn't give a talk on Bay Trail, its upcoming SoC for mobile devices. It's probably waiting for the Intel Developer Forum next week but did give more details on its Atom Z2580, the smartphone version of CloverTrail+. This includes two Atom CPU cores, along with dual-core graphics (Imagination Technologies' Power-VR SGX544MP2), a memory controller, and video encoding and decoding engines. Compared with the previous generation known as Medfield, this went from a one-core/two-thread CPU to a two-core/four-thread design and also improved the memory, graphics, display, and low-power music playback features, including new power management states. Overall, Intel said this provided a twofold improvement in CPU performance and a threefold improvement in graphics. (The benchmark numbers, especially compared with ARM systems, have been controversial.)

I had hoped we would hear more about Bay Trail from Intel—after all it is supposed to be in systems shipping for the holiday season—and perhaps about Kaveri from AMD. But still, when you think of the changes going on in the processor market—a move away from performance as the most important criteria and instead a greater focus on power efficiency and scalability—it has been a rather intriguing year in the processor market.

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